Human machine interface for mission critical wireless communication link nodes

ABSTRACT

A mission critical wireless link (MCWL) node for communicating with a human machine interface (HMI) terminal over a mission critical wireless link is provided. The MCWL node includes a MCWL wireless circuit configured to communicate with a first MCWL node over the mission critical wireless link by employing a mission critical communication protocol; an HMI communication circuit for communicating with an HMI terminal over the mission critical wireless link by employing a short-range communication protocol; a synchronizer for controlling at least a time at which the MCWL wireless circuit and the HMI communication circuit access the wireless link; a multiplexer coupled to the MCWL wireless circuit and the HMI communication circuit, wherein the multiplexer is configured to select any of the MCWL wireless circuit and the HMI communication circuit based on a control signal received from the synchronizer; and a radio frequency (RF) transceiver configured to wirelessly communicate with both the first MCWL node and the HMI terminal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/703,555 filed on Jul. 26, 2018, the contents of which are herebyincorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to the network control andobservability of components within an industrial system, and, moreparticularly, to an implementation of a human machine interface formission critical wireless communication.

BACKGROUND

Industrial systems include a variety of components such as sensors andactuators that are implemented to execute various automated tasks inorder to produce a desired product or carry out a specific process. Eachindividual industrial component is typically controlled either directly(e.g., an actuator may be instructed to move a robotic arm in aparticular manner) or indirectly based on received communications (e.g.,the component may be configured to adjust a process based on a receivedsensor value reading).

As shown in FIG. 1A, an industrial system 100 is used to directindividual connections, e.g., via cables 110, to connect a controller orany computer equipped with Industrial network, such as a programmablelogic controller (PLC) 115 or a Programmable Automation Controller (PAC)(not shown), to each component 120 of the system 100. This is a costlysetup and produces many inefficiencies, as it requires a multitude ofcontrollers even for a single machine having multiple components. Thecontrol signal is transmitted using an analog or a digital signal sentover the individual cables 110. While simple in theory, such a setuprequires high maintenance, high setup costs, and significant amounts oftime spent configuring and setting up each component of the system.

Alternatively, industrial systems, an example of which is shown in FIG.1B, include a mission critical link system 130 with a master gateway (orsimply “master”) 140 connected to a controller 115 and configured tocommunicate with multiple industrial components (“slaves”) 160. Themaster 140 offers a more centralized approach, with a single master 140connected to many slaves 160. The connection may be established overdirect cable connections 150. A standardized protocol, such as IO-Link®,is an example implementation of such a system.

The master 140 is configured to connect to multiple slaves (e.g.,devices that may operate as “slaves” in a master-slave star topology)160, which may be easily connected to actuators, sensors, and the like(not shown). The sensors may include smart sensors providing valuablediagnostic information as well as updated status reports.

However, this setup retains a number of the drawbacks of the oldersystems, most notably the requirement for physical cables to be runbetween a controller and each component of the system. The setup of suchwiring is expensive, time-consuming and can be significantly limiting inmany industrial applications. For example, running cables in a sealed“clean” room used in many industries can be awkward and can compromisethe sealed nature of the room. Further, certain mobile systems thatrequire automated vehicles, e.g., robots configured to move stock orequipment around a warehouse, would be heavily encumbered by requiring aphysical cable be attached to each vehicle.

Due to these limitations, a mission critical wireless link (MCWL)system, an example of which is shown in FIG. 1C, has been developed toimplement a mission critical link system over wireless communication,thereby obviating the need for cumbersome wires. The IO-Link® Wireless(IOLW) specification is an example of a MCWL system and describes atime-division multiplexing (TDM) network configured to communicate withmultiple devices. The master downlink is a single broadcast message permaster track (i.e., one message sent for all devices within a track),while the multiple devices and components use a synchronous (i.e.,synchronized by an external clock) TDM method for uplink. The mastertracks are synchronized and use frequency-division multiplexing (FDM).The master 140 is therefore connected via a wireless link to the variousslaves 160.

Access to slave 160 and master 140 deployed in the MCWL systemillustrated in FIG. 1C can be performed only using devices that supportand/or implement the IOLW's protocol specification. That is, computers,handled devices, or servers can communicate with master and/or slavedevices in the MCWL system only if such devices implement the IOLWprotocols. As such, monitoring or debugging devices, for example, wouldrequire implementing dedicate hardware and software in order tointerface with the devices 140 and 160.

In MCWL systems, it is required to wirelessly connect the master 140 andslaves 160 to a human-machine interface (HMI) terminal. An HMI terminalprovides a user interface or dashboard that connects a person to amachine, system, or device. In industrial machines, an HMI terminal canbe utilized for real time diagnostic, configuration, validation,installation, and debugging.

FIG. 2 shows a wireless connection of an HMI terminal 210 with a mastergateway 220 and a slave 230 in an example MCWL system 200. The HMIterminal 210 may be a standalone diagnostic or configuration tool. Asillustrated, each element requires Bluetooth Low Energy (BLE) radio tocommunication with the HMI terminal 210. Specifically, each of the HMIterminal 210, the master 220, and slave 230 includes a BLE transceiver211, 221, and 231, respectively. The BLE transceiver (radio) operatesaccording to the BLE communication protocol. The master 220 and slave230 each include a mission critical wireless transceiver (222 and 232,respectively) configured to wirelessly communicate using a MCWLcommunication protocol (e.g., IOWL). The transceivers 222 and 232 aredistinct and separate from BLE radios 221 and 231. Thus, each of themaster and slave requires an additional radio component (e.g., a BLEcomponent) in order to communicate with the HMI 210.

This is a major disadvantage since the additional transceiver mayinterfere the operation of the MCWL system, and thus degrade theperformance of the MCWL system. Further, embedding additional radiocomponents increases the cost and may affect the form factor of eachnode (slave and master gateway).

It would therefore be advantageous to provide a solution that wouldovercome the challenges noted above.

SUMMARY

A summary of several example embodiments of the disclosure follows. Thissummary is provided for the convenience of the reader to provide a basicunderstanding of such embodiments and does not wholly define the breadthof the disclosure. This summary is not an extensive overview of allcontemplated embodiments, and is intended to neither identify key orcritical elements of all embodiments nor to delineate the scope of anyor all aspects. Its sole purpose is to present some concepts of one ormore embodiments in a simplified form as a prelude to the more detaileddescription that is presented later. For convenience, the term “someembodiments” may be used herein to refer to a single embodiment ormultiple embodiments of the disclosure. Some embodiments disclosedherein include a mission critical wireless link (MCWL) node forcommunicating with a human machine interface (HMI) terminal over amission critical wireless link comprising: a MCWL wireless circuitconfigured to communicate with a first MCWL node over the missioncritical wireless link by employing a mission critical communicationprotocol; an HMI communication circuit for communicating with an HMIterminal over the mission critical wireless link by employing ashort-range communication protocol; a synchronizer for controlling atleast a time at which the MCWL wireless circuit and the HMIcommunication circuit access the wireless link; a multiplexer coupled tothe MCWL wireless circuit and the HMI communication circuit, wherein themultiplexer is configured to select any of the MCWL wireless circuit andthe HMI communication circuit based on a control signal received fromthe synchronizer; and a radio frequency (RF) transceiver configured towirelessly communicate with both the first MCWL node and the HMIterminal.

Some embodiments disclosed herein also include a method forcommunicating with a human machine interface (HMI) terminal over amission critical wireless link (MCWL). The method comprises determiningif there is an available time interval for a MCWL node to communicatewith the HMI terminal; issuing an HMI grant signal allowing the MCWLnode to communicate with the HMI terminal over the mission criticalwireless link when there is an available time interval; determining ifthe available time interval is assigned for an uplink communication or adownlink communication when there is an available time interval; issuingan uplink control signal to allow transmitting HMI messages to the HMIterminal when the available time interval is assigned to the uplinkcommunication; issuing an uplink control signal to allow reception ofHMI messages from the HMI terminal when the available time interval isassigned to the downlink communication.

Some embodiments disclosed herein also include a mission criticalwireless link (MCWL) system comprising: a first MCWL node configured tocommunicate with a human machine interface (HMI) terminal over a missioncritical wireless link; a second MCWL node configured to communicatewith the first MCWL over the wireless link; and an HMI terminalconfigured to communicate only using a short-range communicationprotocol.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is disclosed herein is particularly pointed outand distinctly claimed in the claims at the conclusion of thespecification. The foregoing and other objects, features, and advantagesof the disclosed embodiments will be apparent from the followingdetailed description taken in conjunction with the accompanyingdrawings.

FIGS. 1A and 1B are diagrams of standard techniques for controllingindustrial components (prior art).

FIG. 1C is a diagram of standard IO-Link Wireless (IOLW) system (priorart).

FIG. 2 depicts a standard solution for providing HMI communication in aMCWL system (prior art).

FIG. 3 is a diagram of a MCWL system utilized to describe the variousdisclosed embodiments.

FIGS. 4A, 4B and 4C are time diagrams demonstrating time intervalsutilized for HMI communication in a MCWL system.

FIG. 5 illustrates channels utilized for HMI communication in the BLEfrequency spectrum according to an embodiment.

FIG. 6A illustrating a communication protocol between an MCWL node andan HMI terminal according to an embodiment.

FIG. 6B illustrating a flowchart of a messaging protocol as implementedby an IOLW node according to an embodiment.

FIG. 7 is a timing diagram of a control signal generated by thesynchronizer according to an embodiment.

FIG. 8 is an example block diagram of an MCWL node designed according toan embodiment.

FIG. 9 is a diagram illustrating a handshake process for establishingsecured authentic channel between an HMI terminal and an MCWL nodeaccording to an embodiment.

DETAILED DESCRIPTION

It is important to note that the embodiments disclosed herein are onlyexamples of the many advantageous uses of the innovative teachingsherein. In general, statements made in the specification of the presentapplication do not necessarily limit any of the various claimedembodiments. Moreover, some statements may apply to some inventivefeatures but not to others. In general, unless otherwise indicated,singular elements may be in plural and vice versa with no loss ofgenerality. In the drawings, like numerals refer to like parts throughseveral views.

The various disclosed embodiments include a human machine interface(HMI) to a mission critical wireless link (MCWL) system using astandardized and commercially available wireless protocol. In an exampleimplementation, such a wireless protocol is a Bluetooth Low Energy (BLE)protocol and the MCWL is an IO-Link® Wireless (IOLW) defined in theIO-Link® Wireless System Specification, first version published in March2018. Thus, the disclosed embodiments allow for connecting an HMIterminal without any dedicated BLE transceiver (radio) by any IOLW nodein a IOLW system. An IOLW node may include a slave or a master gatewayand will be referred hereinafter as a “MCWL node.”

FIG. 3 is an example diagram of a MCWL system 300 utilized to describethe various disclosed embodiments. In the example embodiment shown inFIG. 3, a master gateway 310 communicates with a slave (device) 320 overa mission critical wireless link 340. In example, the protocol employedby the link 340 is the IOLW.

The master gateway 310 communicates with a number of slaves (only oneslave is shown in FIG. 3) over several tracks. To this end, the mastergateway 310 includes a mission critical wireless circuit 312 coupled toan antenna array 314. The antenna array 314 may include one or moretransmitter/receiver (TX/RX) antennas. The master gateway 310 alsoincludes a synchronizer enabling the communication with an HMI terminal330.

Each track may be enabled for time-division multiplexing communicationbetween up to eight slaves. In one configuration, the master gateway 310may include a plurality of receivers (not shown) configured towirelessly communicate with the plurality of slaves; a processingcircuitry (not shown) coupled to the plurality of receivers; and amemory (not shown) containing instructions that, when executed by theprocessing circuitry, configure the processing circuitry to at leastcontrol the operation of the plurality of receivers such that at leastone of the plurality of receivers is configured to receive a pluralityof transmissions from the slaves in succession where a guard timebetween transmissions is substantially shorter than a processing delayof the transmissions by the at least one receiver. An exampleimplementation for allowing a master gateway 310 to communicate with aplurality of slaves using a single radio (circuit 312) is disclosed inU.S. patent application Ser. No. 16/446,004, assigned to the commonassignee, the contents of which are hereby incorporated by reference.

The slave 320 communicates over the spectrum of the industrial,scientific, and medical (ISM) band. The ISM band is a group of radiofrequencies (RF) that are internationally designated for use in theindustrial, scientific, and medical fields. In one such band, thechannels are spaced apart by 1 megahertz (MHz) and extend from2,400-2,480 MHz.

The slave 320 includes a mission critical wireless circuit 322 coupledto a single antenna 324. The slave 320 also includes a synchronizer 325enabling the communication with the HMI terminal 330.

According to the disclosed embodiments, the HMI terminal 330 isconfigured to interface with the master gateway 310 and slave 320 overthe same frequency band as the mission critical wireless link 340. TheHMI terminal 300 may be a laptop computer, a tablet, a smartphone, andthe like. The HMI terminal 330 may be utilized for real-time diagnostic,configuration, validation, installation, and debugging. The HMI terminal330 does not include any means that support the MCWL, and in particularthe IOLW protocol. In an embodiment, the HMI terminal 330 includes atleast a BLE transceiver 335, and therefore can connect and communicationwith other devices (not shown) over the BLE communication network.

Typically, BLE devices are detected through a procedure based onbroadcasting advertising packets. The BLE communication protocol definesthree (3) separate channels (frequencies) in order to reduceinterferences. The advertising device sends a packet on at least one ofthree advertising channels, with a repetition period “the advertisinginterval”. For reducing the chance of multiple consecutive collisions, arandom delay of up to 10 milliseconds is added to each advertisinginterval. A scanner listens to the advertising channels during a scanwindow, which is periodically repeated every scan interval.

According to the disclosed embodiments, the BLE radio 335 in the HMIterminal 330 provides a wireless interface to the master gateway 310 andslave 320 through BLE communication. This is performed by togglingbetween advertise and scan BLE modes at certain time intervals. Thetoggling is managed by a synchronizer (315 and 325). The synchronizer isdesigned in a way such that the controlled time intervals are designedto ensure the fidelity of the MCWL system, thereby allowing the reuse ofthe mission critical wireless circuit (i.e., IOLW radio) for HMIcommunication.

FIGS. 4A, 4B and 4C are time diagrams demonstrating time intervalsutilized for HMI communication in a MCWL system. The assignment ofspecific time intervals the HMI communication is performed by thesynchronizer, i.e., either the synchronizer 315 or 325 in the gateway310 or slave 320, respectively.

As demonstrated in FIG. 4A, a MCWL system implementing an IOLW protocolutilizes a deterministic time profile. The minimal duration of a cycle401 is 5 milliseconds (ms). Each cycle 401 starts with a sub-cycle whichserves process data (PD) 410 of the critical cycle data. Theretransmission mechanism is realized by repetition of the PD 411 in thenext sub-cycle. For example, such repetition demonstrated in the secondcycle 405 shown in FIG. 4A.

For example, according to the IOLW specification, when only the PD istransmitted, the available unused time in a cycle (402) is typically 3.2ms. When the process data (PD) and single repetition is alsotransmitted, the available time interval (403) is 1.6 ms. According tothe disclosed embodiments, during such available sub-cycle timeintervals, the synchronizer can assign an available time interval (412)for HMI communication. The duration of such time interval may be ofabout 1.6 ms.

FIG. 4B depicts a zoom-in of the cycle 401 of FIG. 4A. In this case, thesynchronizer assigns the last sub-cycle time interval (420) for HMIcommunication. The time interval (412) may support transmissions of oneor more packets.

The communication between an HMI terminal and an MCWL node is allowedand performed only within the designated available time intervals.Therefore, the communications to and from a MCWL node does not interferewith the MCWL network. As a result, the performance of the missioncritical data is unaffected.

In an example implementation, an uplink connection is defined from aMCWL node to an HMI terminal (e.g., the HMI terminal 330). In theopposite direction, a downlink connection is from the HMI terminal to aMCWL node. A message on the uplink and downlink connection is performedusing a constant set of one or more BLE packet repetitions.

FIG. 4C is a zoom-in view of an uplink HMI communication packet 420depicted in FIG. 4B. A possible packet structure as used in BLE beacons.The HMI communication packet 420 starts with a PLL transition timewindow (430) to allow frequency setting time, followed by a packet 431.The packet's 431 structure is defined by the BLE protocol. The maximaltime for the HMI communication is limited by the IOLW sub-cycle timeinterval (interval). The duration of such time interval may be between1.664 ms and 11 ms.

In order to support at least 3 consecutive packet repetitions in asub-cycle time interval, a maximal payload of 33 bytes is showed. Thus,the HMI uplink communication allows PLL settling time of 210 microsecond(usec) followed by a maximal packet length of 344 usec, for a total of554 usec (three repetitions within a sub-cycle time interval of 1.664ms).

FIG. 5 is an example diagram 500 of the 2.4 GHz ISM band. The BLEcommunication standard defines 40 frequency channels with 2 MHz spacing.Channels 37, 38, and 39 are the BLE advertising channels. In anembodiment, since one of the two IOLW configuration frequencies overlapsadvertising channel 39 (2,480 MHz), this channel (labeled as 520) is notutilized for HMI configuration. Thus, the available BLE advertisingchannels 37 and 38 (labeled as 510) are the only advertising channelsutilized for the HMI communication. In an embodiment, the advertisingchannels labeled 37 and 38 are blacklisted by the IOLW network to avoidinterferences by the unsynchronized HMI terminals on IOLW network.

FIG. 6A is an example flowchart 600 illustrating a communicationprotocol between an MCWL node and an HMI terminal according to anembodiment. The MCWL node may operate according to the IOLW standardspecification discussed above.

At S610, it is checked whether current time interval is available forHMI communication. The check may be performed by the synchronizer, e.g.,one of the synchronizers 315 or 325 shown in FIG. 3 and depending on theMCWL node attempting to perform the HMI communication.

When current time interval is not available for HMI communication,execution ends. Otherwise, when there is an available time interval, atS620 it is determined whether such time interval is assigned for a BLETX (uplink) (YES) or BLE RX (downlink) (NO) round. In case of an uplinkassignment, an uplink message is sent repeatedly according to a fixedsub-cycle time interval (e.g., 1.66 ms).

At S630, the number of transmissions is initialized, for example as 0.At S640, to allow transmission of each BLE uplink message, thetransmitter's frequency is configured to one of the BLE advertisingchannel (as depicted in 510, FIG. 5). At S650, the packet istransmitted. This process is repeated until the required number ofre-transmissions of packets (S660 and S670) are fulfilled.

In case of a downlink round, at S680, a receiver is set to one of theBLE advertising channels. This allows the receiver to scan for a packetfrom the HMI terminal operating in an BLE scan mode. At S690, a messagefrom the HMI terminal is received and decoded. The receiver may receiveand acknowledge successfully or unsuccessfully reception of suchmessages. A successful acknowledgment of a packet would increase acounter indicating the next message to be transmitted.

FIG. 6B is an example flowchart 698 of a messaging protocol asimplemented by an IOLW node according to an embodiment. At S692, amessage number ‘n’ is transmitted. The message identifier is part of theinformation in the payload bits. This message identifier may betruncated to number of bits enough large to prevent ambiguous decoding.If the followed received message at S694 from the HMI terminal is withthe same message identifier and information, and acknowledge is assertedand the message identifier is increased (S696). If message was notacknowledged or received, then message identifier remains the same.

It should be noted that a receiver and transmitter discussed withreference to FIG. 6 are part of the mission critical wireless circuitdiscussed included in each of MCWL node. An example transceiver(receiver and transmitter) implemented by an MCWL node is shown in FIG.9.

FIG. 7 shows a timing diagram 700 of a control signal generated by thesynchronizer according to an embodiment. The diagram 700 illustrates anadvertising channel 710, an HMI grant signal 720, and thedownlink/uplink control signal 730. The diagram 700 also illustrates achannel utilization 710 of the BLE advertising channels by an MCWL node.

When an HMI grant signal 720 is set (labeled as state 722), there is anavailable timeslot (a current sub-cycle time interval) for an HMIcommunication. When the signal 720 is clear (labeled as state 721), thecurrent sub-cycle time interval is available for the MCWL transmission.The HMI grant signal 720 prioritizes mission critical data transmission.

The downlink/uplink signal 730 is toggled per available the sub-cycletime interval. In the example diagram 700, the toggling is performed oneach available (to HMI communication) sub-cycle time interval. While thedownlink/uplink signal 730 is set (labeled as state 735) and the HMIgrant is also set (labeled as state 722), then the sub-cycle timeinterval is assigned for the downlink.

The utilization of the advertising channel 710 is at a state 711 foradvertising channel 38 (2402 MHz) and at a state 712 for advertisingchannel 39 (2426 MHz). The downlink/uplink signal 730 is at clear state(731) and HMI grant signal is at a set state (722), the sub-cycle timeinterval is assigned for the uplink. The advertising air utilizationsignal 710 is at the clear state (713) for advertising channel (2402MHz) and at a state (714) for advertising channel 2426 MHz. It should benoted that within the minimal time interval of sub-cycle and maximalpayload length a number of three (3) consecutive messages can betransmitted.

FIG. 8 shows an example block diagram of a MCWL node 800 designedaccording to an embodiment. The MCWL node 800 may be either a mastergateway or a device. The example MCWL node 800 includes a MCWL wirelesscircuit 810, an HMI communication circuit 820, and a synchronizer 830coupled to a multiplexer (Mux) 840. The multiplexer 840 is connected toan RF transceiver 850.

The RF transceiver 850 is utilized for communicating with another MCWLnode and HMI terminal (not shown). The selection is based on an HMIgrant signal issued by the synchronizer 830. It should be noted that,when the RF transceiver 850 is implemented in a master gateway, the RFtransceiver 850 can support multiple tracks and include a plurality ofantennas.

The synchronizer 830 is configured to receive the HMI communicationinformation status and an IOLW Active signal which indicates theavailability of the IOLW network. The information status includes the ofACK/NACK of last transmitted message. Based on the information statusand signals, the synchronizer 830 is configured to set the up/down linksignal and the HMI grant signal which serves as an input to the MUX 840.The MUX 840 selects whether to allow IOLW communication or HMIcommunication.

FIG. 9 is a flow diagram illustrating a handshake process 900 forestablishing secured authentic channel between an HMI terminal 910 andan MCWL node 920 according to an embodiment. Both the HMI terminal 910and an MCWL node 920 operate in a BLE mode.

At S901, the MCWL node 920 starts by sending, via the BLE advertisingchannel, a connection request message containing the relevant attributesof the MCWL node. S901 is repeatedly performed until an acknowledgementmessage is detected from the HMI terminal 910. The acknowledge messageis detected at S902.

At S903, authentication and challenge of the HMI terminal 910 isperformed. Once the authentication is completed, the MCWL node 920 andthe HMI terminal 910 can communicate with each other.

At S904, once the secured channel is established, the HMI terminal 910can execute commands to control, monitor, configure, or obtain data, ora combination thereof, from the IOLW device 920. In an embodiment, thecommands may be in a proprietary format. The commands can be executedusing the host controller interface (HCI). The HCI allows transports ofcommands and events between the host and controller elements of theBluetooth protocol stack.

The various embodiments disclosed herein can be implemented as hardware,firmware, software, or any combination thereof. Moreover, the softwareis preferably implemented as an application program tangibly embodied ona program storage unit or computer readable medium consisting of parts,or of certain devices and/or a combination of devices. The applicationprogram may be uploaded to, and executed by, a machine comprising anysuitable architecture. Preferably, the machine is implemented on acomputer platform having hardware such as one or more central processingunits (“CPUs”), a memory, and input/output interfaces. The computerplatform may also include an operating system and microinstruction code.The various processes and functions described herein may be either partof the microinstruction code or part of the application program, or anycombination thereof, which may be executed by a CPU, whether or not sucha computer or processor is explicitly shown. In addition, various otherperipheral units may be connected to the computer platform such as anadditional data storage unit and a printing unit. Furthermore, anon-transitory computer readable medium is any computer readable mediumexcept for a transitory propagating signal.

As used herein, the phrase “at least one of” followed by a listing ofitems means that any of the listed items can be utilized individually,or any combination of two or more of the listed items can be utilized.For example, if a system is described as including “at least one of A,B, and C,” the system can include A alone; B alone; C alone; A and B incombination; B and C in combination; A and C in combination; or A, B,and C in combination.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the principlesof the disclosed embodiment and the concepts contributed by the inventorto furthering the art, and are to be construed as being withoutlimitation to such specifically recited examples and conditions.Moreover, all statements herein reciting principles, aspects, andembodiments of the disclosed embodiments, as well as specific examplesthereof, are intended to encompass both structural and functionalequivalents thereof. Additionally, it is intended that such equivalentsinclude both currently known equivalents as well as equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure.

What is claimed is:
 1. A mission critical wireless link (MCWL) node forcommunicating with a human machine interface (HMI) terminal over amission critical wireless link, comprising: a MCWL wireless circuitconfigured to communicate with a first MCWL node over the missioncritical wireless link by employing a mission critical communicationprotocol; an HMI communication circuit for communicating with an HMIterminal over the mission critical wireless link by employing ashort-range communication protocol; a synchronizer for controlling atleast a time at which the MCWL wireless circuit and the HMIcommunication circuit access the wireless link; a multiplexer coupled tothe MCWL wireless circuit and the HMI communication circuit, wherein themultiplexer is configured to select any of the MCWL wireless circuit andthe HMI communication circuit based on a control signal received fromthe synchronizer; and a radio frequency (RF) transceiver configured towirelessly communicate with both the first MCWL node and the HMIterminal; and wherein the synchronizer is further configured to:determine if there is an available time interval for HMI communicationwith the HMI terminal; determine if the available time interval isassigned for an uplink communication or a downlink communication whenthere is an available time interval; set the RF transceiver to transmitHMI messages on a preconfigured frequency channel when the availabletime interval is assigned to the uplink communication; set the RFtransceiver to receive HMI messages one a preconfigured frequencychannel when the available time interval is assigned to the downlinkcommunication; and set the control signal when there is an availabletime interval, wherein the control signal is set to select the HMIcommunication circuit by the multiplexer, wherein the short-rangecommunication protocol is a Bluetooth Low Enemy (BLE) protocol.
 2. TheMCWL node of claim 1, wherein the preconfigured frequency channel is oneof a BLE advertising channels.
 3. The MCWL node of claim 1, wherein theMCWL node is a slave and the first MCWL node is a master gateway.
 4. TheMCWL node of claim 3, wherein the MCWL node is a master gateway and thefirst MCWL node is a slave.
 5. The MCWL node of claim 3, wherein theMCWL node is a master gateway and the first MCWL node includes aplurality of slaves.
 6. The MCWL node of claim 5, wherein the mastergateway further comprises: a plurality of receivers configured towirelessly communicate with the plurality of slaves; a processingcircuitry coupled to the plurality of receivers; and a memory containinginstructions that, when executed by the processing circuitry, configurethe processing circuitry to at least control the operation of theplurality of receivers, such that at least one of the plurality ofreceivers is configured to receive a plurality of transmissions from theplurality of slaves in succession, wherein a guard time betweentransmissions is substantially shorter than a processing delay of thetransmissions by the plurality of receivers.
 7. The MCWL node of claim1, wherein the mission critical communication protocol is an IO-LinkWireless protocol.
 8. The MCWL node of claim 1, wherein the MCWL node isfurther configured to establish a secured communication channel with theHMI terminal.
 9. The MCWL node of claim 8, wherein the MCWL node isfurther configured to: send, on a Bluetooth low energy (BLE) advertisingchannel, a connection request message to the HMI terminal; perform anauthentication process with the HMI terminal; and establish the securedcommunication channel with the HMI terminal when the authenticationprocess is successfully completed.
 10. The MCWL node of claim 9, whereinthe HMI terminal is configured to perform, in real-time, any one of:diagnostic, configuration, validation, installation, and debugging ofthe MCWL node.
 11. A method for communicating with a human machineinterface (HMI) terminal over a mission critical wireless link (MCWL),comprising: determining if there is an available time interval for aMCWL node to communicate with the HMI terminal; issuing an HMI grantsignal allowing the MCWL node to communicate with the HMI terminal overthe mission critical wireless link when there is an available timeinterval; determining if the available time interval is assigned for anuplink communication or a downlink communication when there is anavailable time interval; issuing an uplink control signal to allowtransmitting HMI messages to the HMI terminal when the available timeinterval is assigned to the uplink communication; issuing an uplinkcontrol signal to allow reception of HMI messages from the HMI terminalwhen the available time interval is assigned to the downlinkcommunication; establishing a secured communication channel with the HMIterminal; sending, on a Bluetooth low enemy (BLE) advertising channel, aconnection request message to the HMI terminal; performing anauthentication process with the HMI terminal; and establishing thesecured communication channel with the HMI terminal once theauthentication process is successfully completed.